Parachute release mechanism



3 Sheets-Sheet l gjvwe/wtoo B; Brawn G. B. BROWN PARACHUTE RELEASEMECHANISM Nov. 4, 1952 Filed April 1, 1947 N: N @Nk Nov. 4, 1952 e. B.BROWN 2,616,369

PARACHUTE RELEASE MECHANISM Filed April 1, 1947 s Sheets-Sheet 2 N @NENov. 4, 1952 G. B. BROWN PARACHUTE RELEASE MECHANISM 5 Sheets-Sheet 3Filed April 1, 1947 mczoumw usE. mu cu m 9 mm mm mm E @Ng 133;! Ml H1330Patented Nov. 4, 1952 PARACHUTE RELEASE MECHANISM Graham E. Brown,Youngstown, Ohio Application April 1, 1947, Serial No. 738,597

1 Claim. (Cl. 102-43) (Granted under the act of March 3, 1883, asamended April 30, 1928; 370 0. G. 757) This invention relates generallyto hydrostatically controlled means for releasing a parachute from amarine mine adapted to be planted on the bed of a body of water from anaircraft in flight and more particularl to a control device of thischaracter adapted to release the parachute from the mine at thetermination of a predetermined interval of time when the mine comes torest at a minimum operating depth of submergence and to delay release ofthe parachute until the mine comes to rest at a greater depth ofsubmergence when the mine descends beyond the minimum operating depth.

In the use of hydrostatically controlled parachute release devicesheretofore devised for the purpose, it has been the usual practice torelease the parachute from the mine either at a predetermined depth ofsubmergence or at the termination of an appreciable interval of timeafter the mine has entered the water, and, in either case, to utilizethe parachute as a drogue to limit the average velocity of thedescending mine to a relatively low value such, for example, as two feetper second. This retarding effect on the movement of the mine throughthe water is particularly desirable in the case of mines havingsensitive firing mechanisms which otherwise might be damaged orprematurely actuated as a result of shocks received by the mine uponimpact thereof with the bed of the body of water.

Release means adapted to be actuated at a predetermined depth ofsubmergence have not been found to be entirely satisfactory in servicefor the reason that the mine may be free to accelerate when theparachute is released at the predetermined depth of submergence and mayreach a relatively high velocity as the mine strikes bottom when thedepth of the water is considerably greater than the predetermined depthof submergence. In such case, the shock upon impact might be sufiicientto damage or prematurely actuate the firing mechanism of the mine.

Hydrostatic control means adapted to be actuated to release theparachute at the termination of an appreciable interval of timecontrolled, for example, by the dissolving of a soluble washer in from20 to 40 minutes have not been found to be entirely satisfactory inservice for the reason that a mine employing such control means may bedragged away from the target area of the mine by channel or tidalcurrents acting on the parachute before the mine is released from theparachute. Mines employing this release means have the additionaldisadvantage in that a demolition crew, acting quickly, may recover themines by fouling the parachutes with a sweep wire before the mines arereleased therefrom.

The foregoing disadvantages of the prior art devices are obviated in thearrangement of the hydrostatically controlled release device of thepresent invention by the provision of an expansible bellows which isair-filled at atmospheric pressure and adapted to be collapsed againstthe opposing force of a calibrating spring by the pressure of wateracting externally on the bellows, the water being admitted into ahousing surrounding the bellows through a restricted orifice in thehousing. The bellows and housing are carried within a chamberedstructure for supporting the mine from the parachute, this structurebeing apertured to receive the surrounding water thereinto and disposedin a region of reduced pressure at the downstream or trailing end of themine as it descends through the water whereby a period of timecontrolled by the rate of flow of the water through the aforesaidorifice is caused to elapse before sufficient pressure is developedwithin the bellows housing to actuate the bellows to a predeterminedreleasing position.

The bellows is adapted, upon movement into the releasing positionthereof, to initiate actuatlon of ball locking means employed toreleasably secure the parachute pack to the aforesaid mine supportingstructure, and the compression and spring rate of the aforesaidcalibrating spring are predetermined whereby the release mechanism iscaused to operate to release the parachute from the mine at a minimumoperating depth and at the termination of a predetermined period of timewhen the mine comes to rest at such depth. If the depth of the water isgreater than the minimum operating depth, however, the parachute is notreleased until the mine either comes to rest at, or descends to, agreater depth of submergence. Whereas, the parachute is not immediatelyreleased upon reaching bottom except in the case of a relatively greatoperating depth, it remains attached to the mine for only a few secondsat other depths for the reason that the entire time delay correspondingto said predetermined period of time, which begins upon entrance of themine into the water, is of the order of approximately 25 seconds.

An object of the present invention is to provide a new and improvedhydrostatically controlled device for releasing a parachute from amarine mine adapted to come to rest on the bed of a body of water.

Another object is to provide a parachute release mechanism for a marinemine adapted to release the parachute therefrom at the termination of apredetermined interval of time when the mine comes to rest at a minimumoperating depth of the mechanism within a body of water and to delaysuch release when the mine descends beyond the minimum operating depth.

Another object is to provide a parachu'te release mechanism adapted todelay release of the parachute from the mine until the mine eitherdescends to a relatively great depth of submergence within a body ofwater or comes, to rest on the. bed thereof at a depth which exceeds aminimum operating depth of the mechanism.-

Another object is to provide a parachute release mechanism adapted torelease the parachute from the mine at the termination of a period oftime controlled by the rate of flow of the surrounding water throughanorifice in the mechanism.

A further object is to provide a parachute re-.- lease mechanismemployingv a pressure responsive device in communication. with thesurrounding waterthrough. an orifice in. the mechanism and adaptedtoeinitiate release of. the parachute from the mine when: the pressureapplied to the device: reachesa predeterminedvvalue.

Afurther. object. resides. in the provision of a parachute. releasemechanism employing pressure responsive. means; in communication withthe surrounding; water through. an orifice in the mechanism and adaptedtotinitiate release of the parachute fromthe; mine when the pressure ofthe water reaches a. predetermined value and at the: termination. of: a.predetermined. interval of time controlled by the rate of flow of thewater throughztheorifice'.

additional object is to provide a parachute release. mechanism havingmeans adapted toinitiate; release of the parachute,- from the mine inresponse to. predetermined. operating conditions and: to effectacomplete release of the parachute therefrom.- immediately and.positively. when such release hasbeen i'nitiated;

The foregoing and still other objects, features and: advantages ofthe-present. invention will be- A come more clearly. apparent. from thefollowing detailed description of a preferred embodiment thereof;reference being. had to the accompanying drawings; wherein:

Fig.1 is; a. view in elevation showing the releasemechanism; of; thepresent invention interconnecting. a parachute pack. to a marine mine;

Eig.. 2.4 is. asomewhatenlarged. sectional view. of the device taken:along the line 2-2 of Fig. 1 and showing the device in; its locked:position;

Fig; 3 is. a view similar to Fig; 2 and showing the: device in thereleasing position thereof;

Fig; 41s: asectiqnal. View taken along the; line t-mrre.

Fig. 5 isgasectional view taken along, the line 5-5 of-'F Fig; 6' is a;sectional view taken along the line 6-6*of,Fig. 2; and

Fig. 'I illustrates graphically the operating characteristicsyof' therelease mechanism and the variation in lapsed; timebefore the parachuteis released from the mine upon striking bottom at different depths.

Referring now-to the drawings for a more complete understanding, of theinvention and more particularly to Fig, 1 thereof, there is shownthereon a marine mine Hlofa type adapted to be planted from an aircraftin flight and having a sensitive firing mechanism such, for example, as

themaeneticneed tyn mechanism; disclos d:

and claimed in the copending application of James B. Glennon et al. forFiring Mechanism for a Submarine Mine, Serial No. 395,230, filed May 26,1941-.

A parachute H is employed to decrease the descending velocity of themine as it falls from the aircraft andato act as a drogue' on the mineas it descends through the water. For this purpose, the parachute may beof any conventional type having a plurality of shroud lines l2 which aresecured to the parachute and on the free ends thereof to the shroud ring[3. The shroud ring l3- has welded, or otherwise secured thereto, ashackle M which is adapted to be hooked onto a hook l5 adapted to bereceived in a clevis l6 and removably secured therein by means of athreaded clevis pin H. The clevis pin is adapted to passthroughregistered openings in the clevis andhook, and isthreadedlysecured to the clevis as at 18. As will appear in greater detailhereinafter, the clevis lfiis releasably secured to v the mine H) bymeans of: a release mechanism generally. designated by the numeral IS.

The parachute It and the shroud lines thereof are contained. within aparachute pack. generally designated. 2|. and comprising a cylindricalhousing 22' which is secured to: the. end housing 23 of the mine bysuitable screws 241 The end housing; in turn. issecured to, the mine:casing 20 by suitable bolts 3.0. The pack also comprises apartition 25::which is rivetedto the housing, 22 as at 26. The partition. has acentral opening 21 for receiving therethrough the hub portion 28 of abell-shaped member 29-for supporting therelease mechanism contained.therein. Member 29 is .securedtothe end housing23' by aplurality ofcircumferentially disposed: bolts 40; and the partition preferably issecured, in turn, to the supporting. member. as by avplurality of screws3!.

The parachute and shroud lines are packed against the; partition 25within the cylindrical housing. 22: and-'releasably retained thereinprior to launching from. the aircraft by means of a cover 32. whichis;secured inplace by a. pair. of flexible cables 33. The cables. aresecured respectively to a pair of cars 34'; in turn, securedin anysuitable manner to the cover 32. The other ends of the cables aredoubled back and substantially bound with a serving cord as at 35. toform eyes adapted'tobe received respectively by a pair of pins 36'. Thepins 36, in turn, are adapted to be received respectively. in apair ofapertured, ears or lugs-3.1 which are secured-to thepack; by. theaforesaidscrews fi. Pins 36' have respectively secured thereto aipair ofarming wires- 38,. the other ends: of whichare adapted-tobesecuredgtogthe-aircraft.

Asythe; cover 32 is secured in place on the pack 2 l', a pair' ofspring; loaded-plungers 39- slideably carried by housing 22indiametrically. opposed rela-tionthereon aremovedinwardly by. the cover32 against the-opposing force of the loading. springs 4tindividualgthereto.

In the operation. of the apparatus thus far described, pins 38 areWithdrawnfrom cars 3-1 individual thereto, by arming; wires 38. as the.mine-fallsaway from the aircraft. This releases cables 33: and permits.the cover 32v tobe forc ibly ejected from, the pack by plunger. 39 underpower of the loading springs 4t. As. the

coverleavesthe pack, it. is caught. in the airstream: and removedsufficiently. from the pack. tocause the parachute tobe removed therefrom by means-of astatic'linenot shown; which:

interconnects; the cover tothe parachute,

Thereafter, the parachute opens to break the free flight of the minethrough the air whereby the mine is caused to approach the surface ofthe body of water at a reduced velocity. As the mine enters the water,water enters the cylindrical housing 22 from the open end thereof andpasses through suitable apertures 42 in the pack partition to fill thechamber formed by a cylindrical housing 22 of the pack and surroundingthe release mechanism IS and end housing 23. Water in this chamber flowsinto the release mechanism i9 by way of apertures 43 in the supportingmember 29.

Referring now to Figures 2 through 6 wherein the parachute releasemechanism is disclosed in detail, it will be seen that the supportingmember 29 has a central bore 44 adapted to receive slideably therewithinthe cylindrical portion 45 of clevis H5. The clevis is releasably lockedto the supporting member 29 by means of a plurality of balls 46 whichare initially carried within an annular groove 47 formed in thecylindrical portion of the clevis by means of a retainer sleeve 3%. Thesleeve is slideably carried within a central bore 38 provided within theSupporting member 29 whereby the sleeve may be moved to the right inFig. 2 sufficiently to prevent the balls from moving out of groove 41and to cause them to seat against the ring 5|. This ring preferably ispressed within a reduced bore 5-2 against a shoulder 53 formed betweenbores 52 and 44 and is formed of a relatively hard material so as toprovide a wear resistant surface for the balls 48, thereby to preventpremature wearing of the coacting surfaces which otherwise might besufiicient to prematurely release the parachute from the mine.

Sleeve 48 has an integrally formed partition 54 which forms a seat for aspring 55 which is also seated within a counterbore 53 in thecylindrical clevis H5. The spring is inserted under compression betweenthe sleeve partition and the clevis whereby the sleeve is urgedyieldably to the left, as viewed in Fig. 2. Partition 54 also serves torestrict leakage of Water into the release mechanism by limiting leakagethereinto by way of the space between the retainer sleeve 48 and borewhereby leakage of water into the control mechanism may be held to aminimum, the entrance of water into the release mechanism preferablybeing entirely by way of an orifice of predetermined size, as willappear more fully as the description proceeds.

Sleeve 48 extends in overlapping relation with the sleeve portion 59 ofbase member 6| which is secured to supporting member 29 by threadedengagement therewith as at 62. Base member 6| preferably is held againstrotation with respect to the supporting member 29 by means of a setscrew 69. Sleeve 48 is releasably locked in the position shown in Fig. 2by means of a plurality of balls 63 which are disposed respectivelywithin a plurality of diametrical openings 63 formed within the sleeveportion 5:). The balls are normally forced into an annular groove 85formed internally of sleeve 43 by means of a locking ring 66 adapted tobe moved slideably within the sleeve portion 59.

The locking ring is formed with an external groove 6'! adapted toreceive the end portions 68 of a pair of spacer rods 69, the endportions of the spacer rods being defined by grooves 1| respectivelyformed therein. Grooves H are adapted to receive the flange portion 12of the locking ring which is formed as a result of the shape of thegroove 61 therein, whereby the looking ring is secured to the rods foraxial movement therewith. The spacer rods are formed with closediametrical tolerances as may be obtained, for example, in the use ofdrill rods whereby the rods may be caused to fit closely and slideablywith apertures 13 respectively provided therefor within the base member6|.

A plate 14 is provided with a pair of apertures adapted to receive theopposite ends of the spacer rods, these ends of the rods beingshouldered and threaded whereby the plate may be secured thereto, as bynuts, 15, in predetermined spaced relation with respect to the lockingring 66. Plate 14 is formed with a reduced diametrical portion 76adapted to form a seat for a calibrating spring 11 which is interposedunder compression between the plate and the flange portion 78 of thebase member 6|, whereby the plate member 14 and the locking ring 66 aremaintained yieldably in the positions shown in Fig. 2.

An expansible bellows 19 is brazed, or otherwise suitably secured, tothe p-latamember 14 as at 8|. The other end of the bellows carries astud bolt 82 which extends through a central aperture 83 formed in thepartition portion '84 of the base member 6|. The stud bolt carries a nut85 and lock washer 86 whereby the bellows may be tightly secured inposition on the partition portion 84.

A pressure chamber 30 is formed about the expansible bellows by means ofa cup-shaped casing 8'! having a flange which is secured to the basemember by a plurality of cap screws 88, a suitable gasket 89 beinginterposed between the flange and the base member to provide awatertight seal therebetween.

The cup-shaped casing is provided with a re strictive orifice 9| ofpredetermined size whereby the time rate of flow of water into pressurechamber 8-9 is controlled so as to cause a predetermined time intervalto elapse before sufficient pressure is developed on the bellows to movelocking ring 66 into the releasing position thereof, as shown in Fig. 3.The spring rate of the calibrating spring TI and. the initialcompression thereof are such as to require a predetermined pressure onthe bellows to move the ring member into the releasing position thereofagainst the opposing force of the calibrating spring. By reason of theaforedescribed construction of the several moving parts of the releasemechanism, leakage of water into the pressure chamber by way of theaforementioned leakage paths is held to a minimum and the flow of waterinto the pressure chamber is controlled substantially entirely by theorifice 9|. The aforementioned predetermined time interval, therefore,may be held to a value such, for example, as 25 seconds with closetolerances.

In the operation of the parachute release mechanism as the mine entersthe water, water passing into the supporting member 29 by way ofapertures 43 therein passes into pressure chamber 80 by way of orifice9|, and the water entering the chamber causes increasing pressure to bedeveloped on the bellows to cause a gradual collapse thereof as the minedescends through the water. When the pressure on the bellows reaches apredetermined value such, for example, as a pressure corresponding to 15feet of water, the bellows has collapsed sufficiently to cause thelocking ring 66 to be moved into the releasing position thereof, asshown in Fig. 3.

1. As the locking ring moves into the releasing position, balls 63- arecammed inwardly of the sleeve portion 59 of the base member 6| by theretaining sleeve 48' which moves to the left to the releasing positionthereof, as shown in Fig. 3, under power of spring 55. As the retainersleeve 48' is retracted, balls 46 are. cammed outwardly of the annulargroove 41 in clevis- Hi, this. also a by orifice 9|, which time delaybegins upon. en-

trance of the-mineinto the water. Accordingly, when the bottom is atgreater depth, the mine continues to descend beyond the minimumoperating depth, but, in such case, the parachute remains attached tothe mine for shorter intervalsof time after the mine comes to rest.

The operating characteristics of the release mechanism and the variationin the lapsed time when the mine bottoms at different depths may best beunderstood by reference to the graph of 1 Fig. '7 wherein the straightline curve 92 represents the rate of increase of the pressure of thesurrounding water assuming that the mine is descending at an averagevelocity of 2 feet per second, and the straight line curve 93- indicatesthe rate of increase of pressure on the expansible bellows 19 as themine descends through the water. Thus, when the mine comes to rest at adepth of 30 feet as indicated by the hori zontal line 94, the pressureon the bellows has reached a pressure corresponding to the. minimumoperating depth of 15 feet of water and, therefore, the mine isimmediately released from the parachute upon striking bottom. Whenbottom is at a greater depth than 30 feet, the mine will nevertheless bereleased from the parachute at 30 feet. Thus, time interval of 15seconds from the moment the mine enters the water until it reaches adepth of 30 feet elapses before the parachute isreleased fromv the mine.

Whenthe mine comes to rest at the minimum operating depth of 15 feetindicated by the horizontal line 95, from the moment that the mine hitsbottom the rate of increase of pressure on the bellows progressivelydecreases and follows the curve 96 untilthis curve levels off at theminimum operating pressure. at 91 Thus, in this case the-entire timedelay of 25 seconds must elapse before sufficient pressure is applied tobellows 1 9' to release the parachute from the mine. and approximately1-7. /2- seconds elapses between the time. the mine strikes bottom at 15feet and the parachute is released therefrom.

When the mine comes to rest at an intermediate depth such, for example,as 20 feet, as indicated by the horizontal line 98, from the moment thatthe mine'hits bottom, the rate of increase of the pressure on thebellows begins to decrease progressively and follows the curve 99 untilit levels off at I!!! ate pressure corresponding to the pressure on thebottom at 20 feet. Curve 99', however, reaches point I02 thereon iii)which is at a pressure corresponding to the minimum operating depth of 15 feet, at the termination of approximately 17 seconds after the mineenters the water. Thus, in this case, approximately '7 seconds elapsebetween the time the mine strikes bottom. and the parachute is releasedtherefrom.. In. any case, a relatively short interval: of time mustelapse between the. time the mine. bottoms and the parachute is releasedfor the reason that the maximum time ofv 25 secon'ds required when themine comes to rest at 15 feet is'relatively' short compared to theseveral minutes required in the case? of parachute release mechanismheretofore devised.

From the foregoing it will now readily be understood that a parachuterelease mechanism has been provided which is well adapted to fulfill theaforestated objects of the invention, and whereas but one structuralembodiment. thereof, which gives satisfactory results, has beendisclosed, it will be apparent to those skilled in the art thatadditional embodiments and modifications thereof may be made withoutdeparting from the spirit and scope of the invention as defined by theappended claim. 7

The invention herein described may be manufactured and used by or forthe Government of the United States of America for governmental purposeswithout the payment of any royalties thereon or therefor,

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

In a parachute release mechanism for a sub marine mine, the combinationof a first locking '7 means including a plurality of balls forreleasably locking the parachute to the mine, a sleeve member forreleasably retaining said plurality of balls in the locking positionthereof and adapted to be moved into a position for releasing the ballsthereby to effect release of said first locking means, spring means foryieldingly urging said sleeve into the releasing position thereof, a secon'dlocking means including a second plurality ofballs forreleasably'lockingsaid sleeve member in the locking position thereofagainst the opposing force of said spring means, means including a ringmember for releasably retaining the second plurality of balls in thelocking position' thereof and adapted to be moved intoa position forreleasing said second plurality of balls thereby to effect release ofthe sleeve member, and means effective in time delayed relation to theentrance of the mine into the water for moving the ring member into thereleasing position thereof.

GRAHAM B; BROWN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS- Number Name Date 1,294,327 Boston et al -Feb. 11,1919 2,413,450 Johnsen Dec. 31, 1946 2,422,5 l8 Hebard June 1'7,v 19472,435,444. Johnse'n Feb. 3, I948 FOREIGN PATENTS- Number Country Date673,422 France Oct. 8, 1929

